1. Field of the Invention
The present invention relates to a hinge, and more particularly to a hinge device suitable for use to support a seat and seat lid of a toilet bowl openably and closably.
2. Description of the Prior Art
Various types of hinge devices have so far been proposed for supporting a toilet bowl seat and seat lid openably and closably. Typical ones of such hinge devices include a combination of a rotating shaft to support the seat and seat lid of the toilet bowl and a cam mechanism provided with a compression spring which acts on the shaft, a combination of a rotating shaft and a torsion spring which acts in a direction of canceling a torque of the rotating shaft being rotated in a predetermined direction, a combination of a rotating shaft and a hydraulic damper which acts on the rotating shaft, or a similar combination.
The conventional hinge device of the type in which only the cam mechanism is allowed to act on the rotating shaft is advantageous in that a matching can easily be attained between a torque generated when the seat and/or lid are operated and a rotation moment of the seat and lid. For a large torque, however, the hinge device should have a large structure.
The conventional hinge device in which only the torsion spring acts on the rotating shaft has an advantageous in that even a small structure of the hinge deice can create a large torque. Since the torque increases and decreases linearly as the seat and/or seat lid are operated, however, no easy matching is attainable between the torque of the seat and the seat lid and a sine curve depicted by the rotation moment of the seat and lid being operated, so that it is difficult to elaborately fit the torque of the seat and seat lid to a curve delineated by the rotation moment of them when being operated and also to provide a appropriately accented operation of the seat and lid being operated.
Further, the conventional hinge device in which only the hydraulic damper is used to act on the rotating shaft is not advantageous in the difficulty of elaborately fitting the torque of the seat and seat lid to a curve depicted by the rotation moment of them and also of providing an appropriately accented motion of the seat and lid being opened or closed, for example, stopping and holding the seat at an intermediate angular position, and braking the seat having been opened to a predetermined angular position.
To control the rotation moment of the openable/closable body such as a seat and seat lid of a toilet bowl in order to softly close the openable/closable body, the Inventor of the present invention proposed a hinge device for use to support the seat and seat lid of the toilet bowl openably and closably, comprising a hinge case, a rotating shaft rotatably provided inside the hinge case, a stationary cam having the rotating shaft penetrated through the center thereof and fixed inside the hinge shaft, a rotatable sliding cam having the rotating shaft penetrated through the central portion thereof to be slidable axially and rotatable with the rotating shaft, and an elastic means for urging the rotatable sliding cam towards the stationary cam, the hinge device comprising a damping means consisting of a rubber ring fitted on the rotating shaft and between the rotating shaft and hinge case and a viscous oil applied between the rubber ring and hinge case, the damping means being allowed to act on the rotating shaft.
In this hinge device, a pressure under which the rubber ring is urged to the inner wall of the hinge case can be adjusted to control the torque of the rotating shaft. However, this hinge device is disadvantageous in that it is only applicable to a hinge device in which such a rubber ring is used.